The present disclosure relates to an imaging apparatus and an imaging system.
Recently, in a widespread single-lens reflex type digital camera, a kind of filter such as a quartz lowpass filter and a glass ND (Neutral Density) filter is interposed in a contact portion between a lens apparatus and a camera body. That is, for the digital camera, a glass substance having a thickness of about 3 mm to about 4 mm is inserted in the contact portion between the lens apparatus and the camera body.
On the other hand, for a film camera, no substance, namely, air, is interposed in the contact portion between the lens apparatus and the camera body. It is believed that the contact portion between the lens apparatus and the camera body has the thickness of 0. Thus, the film camera differs largely from the digital camera.
Generally, many lens apparatuses used in a movie camera are designed for the film camera. In the lens apparatus for the film camera, an aberration is corrected such that the camera is brought into focus in the condition that the glass filter is not inserted in the camera.
On the other hand, recently, a digital movie camera is becoming widespread. In these situations, frequently, the lens apparatus for the film camera is mounted on the digital movie camera in which the filter is inserted. In this case, a spherical aberration varies according to the filters incorporated in the camera. As a result, the best image is obtained in a position different from an original focus position of the lens, and the focus position is deviated.
As to the spherical aberration variation caused by the filter incorporated in the camera, it is conceivable that the focus position is corrected by an amount corresponding to the varied aberration using an AF (Auto Focus) system (for example, see Japanese Patent Publication Laid-Open No. 2007-243934).